The present invention relates to an image forming apparatus to which replaceable parts are detachably provided.
A conventional image forming apparatus such as a printer is configured to perform a correction operation of an image density (i.e., an image density correction operation) or the like, in order to maintain printing quality. The image density correction operation is performed by forming a special pattern (i.e., an image density detection pattern) on a feeding belt using a toner and by detecting an image density of the image density detection patter by mean of an image density detection unit (see, for example, Japanese Laid-Open Patent Publication No. 2004-258281).
The image forming apparatus includes a toner cartridge in which a toner is stored. The toner cartridge is a replaceable part which is detachable from a main body of the image forming apparatus. When the toner stored in the toner cartridge is used up, the toner cartridge is replaced with a new toner cartridge for replenishing the toner to the image forming apparatus. As a new toner cartridge, it is preferable to use a genuine part (i.e., a genuine toner cartridge) supplied by a manufacturer of the image forming apparatus, since the performance of the genuine toner cartridge is assured by the manufacturer of the image forming apparatus. However, as with other replaceable parts of the image forming apparatus, there are non-genuine toner cartridges supplied by other manufacturers. Therefore, there are cases where a user may inadvertently use a non-genuine toner cartridge.